Entretien : Huile, Refroidissement et Allumage
Source : RX8Club.com - New and Potential Owners START HERE! Auteur : RIWWP
The Oil Burning Story — La consommation d'huile
One of THE MOST pervasive complaints about the RX-8 is how it burns oil. Everything from neighbors to arm chair racers to magazine editors like to rave and complain about how much oil the RX-8 burns.
Well, it's true. The RX-8 does burn oil. However, this isn't actually a problem, and no, we haven't deluded ourselfs into believing that some oil burning is "ok".
The RX-8 burns oil intentionally. After all, the engine seals are inside the combustion chamber! The only way to to lubricate the seals inside the combustion chamber is to inject oil (or have oil in the fuel, called premix). This oil then gets burned under combustion, so it has to keep oiling, and oil keeps burning. On average, you should see about a quart of oil burned every 1,000 miles. If you aren't burning anywhere close to this, something is wrong. If you are burning way less, you aren't getting enough oil injected, and your engine doesn't have much chance of lasting long. If you are burning way more, then either you intentionally increased the oil injection and it isn't an issue (1 qt every 500-900 miles), or you have an oil control ring failure, and oil is leaking into the housing (1 quart every 200-400 miles), or have a severe vacuum problem where the engine is actively sucking oil into the intake. An oil control ring failure will require an engine rebuild to fix, although isn't inherently bad. You will have more oil smoke, you will burn oil faster, your plugs will get fouled faster so your coils won't last as long, but not much else. Let your oil run too low though, and you can fry your engine from being too low on oil.
Keep the oil filled above the 1/2 full mark, letting the oil light come on means you are already critically low. Don't overfill though, since overfilled oil spills into the intake and gums up your intake valving, and can easily cause costly repairs. It is also recommended that you use a long necked funnel when you add oil to prevent oil from going down the vacuum line instead of into the engine.
Another point to consider though, is that nearly all performance cars out there burn some oil. Most trucks do, many commuter cars do.
Toyota considers burning 1 quart every 1,000 miles within acceptable burn rates.
Ford considers burning 1 quart every 1,000 miles within acceptable burn rates.
BMW considers burning 1 quart every 1,000 miles is actually fairly good.
Porsche considers burning 1 quart every 1,000 miles within acceptable burn rates.
Do a search for any car you want and "excessive oil consumption". Read the stories people have, and when a dealer has told them that the oil burn rate they are seeing is "completely acceptable."
Time and time and time against you will see that 1 quart every 1,000 miles is pretty damn common! But, for some reason, these engines that aren't supposed to be burning oil don't get hammered for burning it (probably because people just don't notice, thanks to a large oil pan), and the RX-8 gets hammered for intentional oil injection by everyone in sight.
Which Oil to Use — Quel huile utiliser
The most debated question in the community, bordering on a religious war, so I won't try to cover every point here.
It boils down to deciding for yourself.
Some go with 5w20, to stay with Mazda's recommendation in North America. Some go with 5w30 to go with Mazda's recommendation outside North America. Others go to 10w40 or even 20w50, the most common weights among RX-7s. The general argument revolves around if 5w20 is too thin or not. Typically, you want to go with a heavier weight oil (higher numbers) the hotter the environment you live in. Many manuals outside of North America state something to this effect. So research up on it, and make your own decision.
Dino vs synthetic is another hot topic, with the main argument revolving around if the strength of the synthetic is worth the cost, and if there is any better burning (or not better burning) than dino oils, and if any deposits are left behind that could increase engine wear. Mazda only recommends non-synthetic, but does not require it. Your decision.
And yes, all weights of oils mix with all other weights of oils, roughly averaging the numbers. Half 5w20 and half 5w40 is roughly 5w30, for example. Not precisely, but close enough. Dino also mixes entirely fine with synthetic.
And you know what the kicker is at the bottom of this whole oil debate pile?
It doesn't really matter
Fresh oil on regular changes is far far far more important than ANY of the above attributes. And the only impact that crankcase oil type and viscosity lubrication has on your engine's lifespan is bearing wear, which is not a severe concern for us, since we have numerous other methods of engine failure that have nothing to do with oil attributes!
Outside of lubricating the e-shaft bearings and being available for injection into the combustion chamber (where none of the attributes above matter at all), the oil's benefit is a secondary method of assisting to keep our engines cool. Oil is fantastic for transporting heat out of the engine. And all types and viscosity do that equally well, or as close to equally as won't make a tangible difference.
There are claims that synthetic doesn't burn as cleanly as dino.
Well, are you really going to argue that filthy dirty 4-stroke dino oil burns cleaner than filthy dirty 4-stroke synthetic oil? NEITHER of them were meant to be burned, and crankcase oil is very very filthy. If you are so concerned about how clean burning your oil is, then get a SOHN adapter and start burning clean 2-stroke! Then you can pick the oil that you want for the high stress, high rpm, high sheer environment of the e-shaft bearings.
So if oil weight matters to you, then do some reading on the various opinions, find an opinion you somewhat agree with that is made in reference to the climate you drive in, the drive style you do, and your budget, and go with that.
Interested in looking at oil testing data?
There is a fairly limited amount of actual test data about oil. What we do have is used oil analysis tests, by companies like Blackstone Labs. These tests measure the amount of contaminates in the oil, things like water, gasoline, wear metals, sulfur, etc... They give a pretty good idea of how well the oil you are sampling protected your engine. The discussion thread about the tests is here: Used Oil Analysis - Post Them Here
Discussing Oil
Oil discussions are generally frowned on by established members. The problem is that there are so many opinion, no consensus, very limited testing, lots of myths, and a colossal amount of misunderstanding. The "oil war" hasn't really ended, and never will. Please just let it be a "cold war" however, and avoid trying to argue about it in random threads.
If you, a new member or a new owner, REALLY want to discuss your oil choice, please do it here: New Member Oil Thread
Cooling Cooling Cooling! — Le système de refroidissement
It is my opinion that more Renesis engines are lost due to cooling system failures than anything else. Perhaps it was not always the case, but as a larger and larger percentage of RX-8s are well past the normal cooling system lifetime, there are more failures occurring from that than anything else.
Que signifie "défaillance du système de refroidissement" ?
The rotary generates a LOT of heat. All this heat has to be shed somehow, and it's the cooling system that needs to do it. The major parts of the cooling system are:
- Radiator (Sheds heat from the water it sees)
- Thermostat (sends water that is hotter than the target temperature to the radiator to be cooled)
- Water Pump (belt driven from the e-shaft pulley, pushes water through the engine)
- Overflow or Expansion bottle (removes air from the system and provides a filling point)
- Coolant lines (rubber or silicone hoses that allow the water to remain contained as it moves around the engine bay)
If even one of these components fails, at all, even in a slight way, it is possible for you to lose your engine.
Our coolant seals are really only trustworthy to a coolant system temperature of about 220F (104C). Past that, you have an increasing risk of having one fail from the heat. If you pass about 240F (115C), you have an additional risk of warping the rotor housings, which is even worse. Making this all much worse, is the fact that our factory coolant temperature gauge (the one in the instrument cluster) won't start moving off of 'center' until 235F-240F (113C-115C).
So far too many owners expect to rely on that gauge to tell them if there is a problem, and expect that there is only REALLY a problem if it gets all the way to the right. All the way to the right is 300F+. If you think about his combination a bit, you can see why so many engines are lost due to cooling system failure.
Comment connaître la température réelle du moteur ?
OBD2 is the answer. OBD2 is an emissions compliance standard that has existed within the US since 1996, and ALL cars that are sold in the US since then are required to be compliant with it. An engine that is operating near 200F produces less emissions than one that is operating lower than 170F, or higher than 240F. The end result of the standard means that the actual coolant temperature is reported through the CAN BUS network, and is available on the OBD2 port. You can get an OBD2 device that reads live data, and get the actual engine coolant temperature. The best way of getting at this data is through a bluetooth OBD2 adapter. Plug it in, no wires to deal with, and then pair your smartphone or tablet to the OBD2 adapter. Then download any one of the numerous free OBD2 apps ('Torque' is the best for Android), and you can get a full readout on nearly everything that the ECU can report. You can read/reset CEL codes, read live data, and record data logs. Highly recommended. Bluetooth OBD2 adapters start around $20.
Monitoring OBD2 — L'outil indispensable du propriétaire RX-8
La jauge de température du tableau de bord est pratiquement inutile. Elle reste au centre entre ~140°F et ~235°F (60°C à 113°C). Quand elle commence à bouger, le moteur est déjà en zone de danger.
La seule solution : un adaptateur OBD2 Bluetooth + une application smartphone.
Materiel recommande
| Element | Recommandation | Prix |
|---|---|---|
| Adaptateur OBD2 | BAFX 34t5, Veepeak OBDCheck BLE, ou équivalent | $20-40 |
| Application Android | Torque Pro (la meilleure pour RX-8) | ~$5 |
| Application iOS | OBD Fusion ou DashCommand | ~$5-10 |
Parametres critiques a monitorer en permanence
| Parametre OBD2 | PID | Zone normale | Zone de danger |
|---|---|---|---|
| Température liquide de refroidissement | ECT (01 05) | 180-210°F (82-99°C) | > 220°F (104°C) = risque coolant seal, > 240°F (115°C) = risque déformation logement |
| Température d'admission | IAT (01 0F) | Ambient +10-30°F | — |
| Régime moteur | RPM (01 0C) | — | — |
| Trims carburant (court terme) | STFT (01 06/07/08/09) | -5% à +5% | > +10% = possible fuite d'air, injecteur bloqué, ou problème O2 |
| Trims carburant (long terme) | LTFT (01 06/07/08/09) | -5% à +5% | En permanence > +10% = le moteur compense un problème |
| Avance à l'allumage | Timing Adv (01 0E) | — | Sauts erratiques = possible raté d'allumage |
| Codes d'erreur | DTC | Aucun | Tout code = investiguer immédiatement |
Configuration Torque Pro pour RX-8
- Configurez un écran de tableau de bord dédié avec : ECT, STFT, LTFT, RPM
- Réglez une alerte visuelle quand ECT dépasse 220°F (104°C)
- Enregistrez les logs de données lors des trajets — utile pour diagnostiquer les problèmes intermittents
Autres usages de l'OBD2
- Lire et effacer les codes CEL — bien plus pratique que d'aller chez le concessionnaire
- Vérifier la santé de l'allumage : des STFT très positifs à haute charge = combustion incomplète = bobines faiblissantes
- Détecter une fuite de vide : STFT élevé au ralenti qui se normalise à haut régime
- Surveiller la pompe à essence : des ratés soudains à haute charge avec STFT négatifs = possible fuel starvation
Comment prévenir les défaillances du système de refroidissement ?
Proper maintenance of your cooling system is CRITICAL. Annual cooling system flushes are important if you aren't using Mazda's FL-22. (Why FL-22? Read this thread) Every 2 years is acceptable if you use that. Mazda says their coolant is good for 5 years, but $40 in coolant isn't worth the risk of a $4,000 engine is it? DEFINITELY replace the coolant by 60,000 miles if it hasn't. Regular coolant flushes will help prevent other cooling system components from failing, however, they will still fail in time.
The thermostat is often the first to go, and is a $65 part (at most). I personally recommend upgrading to Mazmart's 172F thermostat to give your system a bit more head-room, but don't go lower than 170F for the thermostat, or you will be causing CELs, poor gas mileage, and power loss (the ECU is expecting at least 170F when up to temp).
The coolant bottle is also a common failure point, though usually in the coolant level sensor before a pressure problem with the cap. The sensor is integrated into the bottle, so if your coolant light keeps coming on and your coolant is full, then the sensor has just failed. Replace the bottle with a new bottle and cap for $130ish from Mazmart. WARNING: Regardless of if you or someone else does the replacement, there is a little hose that runs from the front of the bottle to the top of the radiator. This hose is stronger than the radiator nipple it connects to. CUT the hose in half and remove the two halves independently, because breaking that radiator nipple means you HAVE to replace the radiator. It can not be repaired. Mazmart has a bottle listed that includes this small hose for this very reason.
The radiator is next, and typically when it starts to fail it will tend to just slowly clog up, with less and less surface area actually shedding heat. A replacement OEM spec radiator is available from Mazmart for $150 (MT, the AT is slightly more). Avoid Mishimoto, it is a well known brand, but it is inferior to OEM, AND more expensive. If you want to upgrade, talk to BHR. They developed an upgrade in the Arizona heat that will outperform OEM and last longer.
If you are replacing the radiator, might as well replace the coolant lines too. They can sludge up in several points and cause their own problems. Typically something else will fail first, but if you just replace other parts and not the lines, the lines won't be all that far behind, and might destroy the new parts you installed. Silicone lines will run you around $300, rubber lines are far cheaper. Keep in mind that there are 9 major coolant lines, so most coolant line kits you see that are 3 piece obviously aren't sufficient. Even the 6-piece kits won't have critical lines replaced. The best bet is to order all new OEM lines individually, rather than a kit.
Que faire si l'aiguille bouge ?
Just because the needle moves and you are in danger territory doesn't mean that you automatically have engine damage, but it's likely. Cases have been known where people have avoided damage. It isn't likely though. Once you have fixed the cooling system, you need to test for coolant seal failure. Pressure test the cooling system is a good way (most corner shops), as long as you know that every single other part of the system is fine. Otherwise, get the oil tested (Blackstone Labs) for coolant, get the coolant tested for combustion gasses (most corner shops), and inspect the plugs for the presence of coolant after it sits overnight. Failing any of these means you need a new engine or an engine rebuild.
If you are only overheating when stopped or at a low crawl, the problem is most likely a fan airflow problem. Either the fans are running when they should be, or your radiator is getting blocked. Safely stop the car and shut the engine off and see if you can find an obstruction to the radiator or fans.
If you suffer a catastrophic cooling system failure that starts spraying coolant everywhere, shut off the car immediately. It is highly unlikely that you will avoid engine damage, but it's possible. As little as 10 seconds of running without coolant in it can be terminal for the engine.
In case it hasn't been clear enough yet, you CAN NOT let your RX-8 overheat.
Premix — Le prémélange huile 2 temps
Premix thread: Gas/Oil Premix Thread
Premix is mixing 2-stroke oil with the gas in the gas tank to assist with lubrication of the apex seals. Why 2-stroke? Because 2-stroke (in general) is designed to be burned. Unlike 4-stroke that you use in during oil changes. Why premix? This gets a bit more vague when answering. The short answer is as noted, to assist with apex seal lubrication. But do we need it? That's a tougher question to answer with facts. Some people swear by it, others do just fine without it. Series 1 has 2 injectors pointing at the side seals, Series 2 adds a center injector to help with lubricating the center of the apex seal. Mazda added this, so they must have found excessive wear in the center of the apex seal, so it's circumstantial evidence for the need to premix. It's hard to say if this will save your engine from apex seal wear failure though. About the only confirmed difference premixing really makes is that the carbon buildup inside the engine appears to be "softer". In theory, makes it easier to clean, and if it comes off it won't come off in dangerous flakes that could cause carbon lock.
Quel premix utiliser ?
The list below is ordered from most ideal at the top, least ideal/not recommended at the bottom.
-
Idemitsu Premix — Generally considered to be the best out there. The only draw back to it is accessibility in that you have to order it, and there are minimum order quantities. Often a member here will order a larger case and split it with locals.
-
Amsoil Saber Pro — Highly regarded, and a bit easier to get than Idemitsu.
-
JASO FC and ISO oils — Basically other oil brands of the same type and grade as the two items above. May be easier to obtain than those.
-
TWC-3 Oils — Usually easy to find, however it's not likely that you are doing much good with them. Not much harm, but small engines that require this type of oil can fail due to lack of lubrication from it.
Originally Posted by Emery_
I think some things should be clarified, after several PM's between me and STEALTH and doing some online research on TCW-3. It is definitely designed to be burnt and fully combust without leaving any residue or ash (if it is a synthetic ashless oil). It is made WITHOUT any metallic additives, as it is meant to burn ashless it does not contain any.
While it probably wouldn't do any harm to the car (besides the catalyst), the problem with TCW-3 lies within it's lubricating capabilities. It is not as good as an oil at lubricating as a ISO or JASO FC certified oil is. TCW-3 is an oil that is not good enough to lubricate snowmobiles and motorcycle engines, and has lead to failure to those engines that TCW-3 oils were used in. Not because the oil itself caused the failure, it just didn't serve it's purpose in lubricating the bearings and engine parts that needed lubricity, hence the failure.
So what I'm trying to get at is... TCW-3 oils suck as a lubricating oil. A JASO FC and ISO oil would do a much better job. TCW-3 premix is not the worst thing you can put in the car though, it shouldn't harm it, and it should lubricate some what, but it just isn't the best lubricant we would want for our engine.
If you were using TCW-3 oils as I was, you should definitely switch to something else like idemitsu or any other 2-cycle oil JASO FC or ISO rated.
-
Marvel Mystery Oil (MMO) — Common, and easy to obtain. Some people swear by it, others denouce it totally. It probably doesn't have much lubrication compared to some of the other options above.
-
Lucas Upper Cylinder Lubricant (Lucas UCL) — A non-oil you can find out there, but we can't recommend it. We can't prove that it causes any fuel filter problems, but for some unknown reason it shows up in a significant percentage of fuel filter problem threads.
Quelle quantité de premix ?
The standard amount is about 1oz for every 2 gallons of gas. Some people go 1oz for every 3 or 4 gallons, and some go for 1oz to 1 gallon. 1oz for 1 gallon is getting on the high end though, so don't just use that to use it. Dig into why you want that much. One of the common reasons for going to 1oz to 1 gallon is for a track day. Lots of heat means a bit better lubrication could be a good thing in the end.
Note that these values are for how much fuel you are putting into the gas tank. So if you are filling up at halfway and adding 7 gallons, then about 3.5oz is ideal. If you never fill till the light comes on, then around 6.5oz is more accurate.
Warm It Up Before Hard Driving — Montée en température
This is true for ANY car out there. Not just rotaries. Let the car warm up before you start mashing the throttle or revving the snot out of it. Keep light on the throttle and under 4k rpm until the water temp needle is pointing straight up (or however slight off of straight is normal for your car). Even then, technically the oil temps aren't fully up yet, but they are getting there. Mazda actually put a lower rev limit when the water temp is under a certain point to help reinforce this. The 2004-2008 RX-8s have a rev limit of ~5,500 rpm until the water temp reaches 100F (I think, might be off). The 2009+ RX-8s have a 2 stage rev cut, at 5,000rpm and 7,000rpm I believe, each at a different water temp point. This doesn't really mean that it's 100% safe just because you have cleared the rev limit, so give it some time, take it easy, and let it warm up. No need to let it idle warm (though some do), light throttle driving is just fine.
Importance of Ignition Health — L'importance de l'allumage
READ THIS!!!!
One of the most often overlooked or ignored parts of RX-8 ownership is the health of the ignition system. This includes the ignition coils, spark plug wires, and spark plugs. They fail. Often. So often as to be critical parts of regular maintenance.
Before I detail why, check out the first post of this thread here: Impact of Old Coils, Wires, Plugs (owner's post here: post #189)
The owner's power dropped from 199whp to 172whp JUST from failing ignition. That's a 13.5% power loss!
Mazda officially lists the plug wires and plugs as part of regular maintenance, but not the coils. Many dealers STILL don't know how easily the coils can fail. And they fail about the same time as the wires and plugs, which is about every 30,000 miles. Some can last longer, some shorter, and it's more related to your total RPMs than it is to your mileage.
When coils fail, they don't suddenly shut off. They start producing weaker pulses scattered among strong ones. The rate of weak pulses slowly increases and pulses start getting dropped entirely, which is where misfires start. All of this means that you aren't burning all the fuel and aren't using all the air that the engine pulled in for that combustion, and it unburnt fuel and air gets dumped into the exhaust, where it happily ignites with the presence of plenty of heat. This saturates the cat in both fuel and heat, and will rapidly kill the cat (A $1,300 USD replacement). Continuing to drive on a failing cat will add other problems such as engine damage and vehicle fires.
Symptoms of ignition failure include: Power Loss, mileage drop, unstable idle, bad idle, inability to idle, shaking at idle, unstable high rpm, misfiring, flashing CEL, coughing engine, glowing cat, flooding, inability to start, inability to pass an emissions sniffer test.
Où acheter des bobines d'allumage ?
| Option | Description | Prix approx. |
|---|---|---|
| BWD/Intermotor (moins cher) | Bobines OEM vendues par le fabricant d'origine. 4 coils + 4 plugs + 4 wires ~$190-220 | ~$190-220 |
| BHR Ignition Upgrade (meilleure upgrade) | Élimine le remplacement périodique, étincelle plus forte. Fils inclus, plugs en plus (~$80). | ~$580 |
| Mazmart OEM (OEM fiable) | Dernière révision OEM (C) des bobines, service client au top. | ~$250 (coils only) |
| Concessionnaire (plus cher) | ~$300+ coils, ~$500+ coils+wires+plugs, ~$700-1,800 avec installation. Pas garanti d'avoir la dernière révision. | $700-1,800 |
| Ebay (plus risqué) | Contrefaçons fréquentes, morts à l'arrivée, aucun support. "Motor King" = inefficaces. "Mazda" sur Ebay = souvent contrefaits. | Risqué |
Bougies (Spark Plugs)
Always go with OEM plugs. The only reason to go with anything else is if you are turbocharged or supercharged, have researched ALL the options, and decide to go with something different. Even most FI setups use OEM plugs.
NGK brand, two each of:
- RE9B-T <- (trailing / top plugs)
- RE7C-L <- (leading / lower plugs)
Price range is $18-$20 for each plug typically, $72-$80 + shipping total.
Note: Be wary of "LSx D585 coil upgrades", as not all D585 coils are created the same, and the standard generic D585 coil is not properly designed internally for the RX-8's ignition needs. They generally "work", but there are anomalies and performance issues. Definitely NOT a plug and play option.